Cardiovascular System Flashcards
What is connective tissue?
matrix plus cells/formed elements
What is plasma?
liquid matrix of blood
what are Cells
formed elemnts of blood
What are the functions of the cardiovascular system?
- transportation: dissolved gases, nutrients, hormones and metabolic wastes
- regulation of pH and ion composition of interstitial fluids
- restriction of fluid loss at injury sites (clotting)
- defence against toxins and pathogens
- stabilisation of body temperature
Recycling of RBCs
- macrophages of liver, spleen and bone marrow monitor quality and engulf old RBCs
- each component of haemoglobin molecule is recycled
- globular proteins disassembled into amino acids and released for other cells to use
- heme units are stripped of iron and turned into biliverdin (green in bruises)
- biliverdin is turned into bilirubin (orange/yellow of jaundice) and transported to the liver - excreted as bile
Functions of blood types?
- plasma membranes contain surface antigens
- antigens enable the immune system to recognise them as ‘self’
- antibodies in the plasma recognise antigens as ‘self’ or ‘foreign’
- blood ‘type’ - classification determined by presence and absence of antigens on red blood cell plasma membranes
- RBCs have 50+ surface antigens, three of which are important : A, B and Rh (or D)
Type A blood
Surface antigen A only, Anti B antibodies in the plasma
Type B blood
Surface antigen B only, Anti-A antibodies in the plasma
Type AB
Both surface antigen A and B, neither Anti-A nor Anti-B antibodies in the plasma
Type O:
Neither Antigen A nor B, both Anti-A and Anti-B antibodies in the plasma
What is the thorax comprised of
wall comprises: 12 thoracic vertebrae [posteriorly], sternum [anteriorly] and ribs [anterolaterally]
- inlet [root of neck] and outlet [diaphragm]
- encloses heart and lungs - some protection for spleen, liver and kidneys
- provides attachment for pectoral girdle and upper limbs
- able to contract and expand during respiration
What cross-reactions can happen in transfusions
- when a plasma antibody meets its surface antigen the RBCs agglutinate (stick together) and haemolyse (rupture)
- clumps and fragments of RBCs can then block small blood vessels
- compatibility of donor and recipient is essential
- surface antigens on donor RBCs are more important than antibodies in donor plasma
Rh negative (Rh- )
indicates absence of this surface antigen of the RBC
Rh positive (Rh+ )
indicates presence of Rh antigen on surface of the RBC
Haemolytic Disease of the newborn
- can arises when Rh-negative woman is carrying an Rh-positive fetus
- when fetal and maternal blood mix at delivery (or antepartum haemorrhage, amniocentesis) the mother recognises fetus’ Rh antigens as being foreign
- mixing of blood can stimulate mother’s immune system to produce anti-Rh antibodies (sensitisation)
- if mother has another Rh-positive fetus her anti-Rh antibodies cross the placenta and attack (haemolyse) fetus’ red blood cells
- anaemia and high levels of bilirubin producing jaundice – can cause death
- administer anti-D antibodies to mother during pregnancy and after delivery
- will destroy fetal RBCs that enter maternal circulation
- no sensitisation, no antibodies
What is the sternum
- bony plate anterior to the heart - palpable [subcutaneous] in parts
- It has three regions: manubrium, body (gladiolus), xiphoid process
- Other features include a jugular notch and a manubriosternal junction/joint
Ribs?
- 12 pairs
- articulate posteriorly with bodies and transverse processes of vertebrae
- articulate anteriorly with their costal cartilages
- costal cartilages (hyaline cartilage) attach rib to sternum
- head - portion of rib that articulates with bodies of thoracic vertebrae. It has superior and inferior articular facets
- neck - narrow portion distal to the head
- tubercle - wider, rough area distal to the neck which articulates with transverse costal facet of vertebra
- angle - lateral curve of rib
- shaft - long, sloping, blade-like portion of rib.
- costal groove on inferior margin of shaft
